GB2036155A - Road forms - Google Patents

Abstract

A road form, for use in the construction of concrete road ways comprises an elongated metal member (1), and a cover member (11). The cover member is a plastics material and has two longitudinal flanges (12, 13) which are, parallel with one another and which intersect a longitudinal web (14) to form two sharp right-angle corners. The cover member is attached to the elongate metal member by clip portions (16). <IMAGE>

Description

SPECIFICATION Improvements in road forms The present invention relates to improvements in road forms for use in the construction of roads, in particular concrete roads.

Concrete roadways are usually constructed in sections, each of which has to be provided with shuttering to form the edges of the section into which the concrete is poured and by which it is contained until set. It is known in the art to use what are termed "road forms" to construct the necessary shuttering.

These road forms consist of an elongate channel section, usually mild steel, which are interconnected and staked into position to define the position and level of the edges of the concrete. The channels are laid with their webs vertical and form a flat edge for the concrete.

A problem with the existing road forms is that, when the sheet metal from which these channel sections are constructed, is bent a relatively large external radius is formed.

Concrete is poured between these forms and then levelled off. Unfortunately when the road forms are removed after the concrete has set a lip remains where the concrete has filled the space created by the presence of the radius.

The lip is, more often than not, chipped off when the road forms are removed because it is relatively small, and this gives rise to the formation of a gap between adjacent sections.

It is an aim of the present invention to provide a road form which is as strong as existing road forms and as easily produced and yet does not give rise to this problem.

According to the present invention there is provided a road form comprising an elongate metal member and a cover member of a plastics material adapted to fit onto at least part of the metal member, the cover member having at least two surfaces lying in different planes which intersect to form a sharp external corner.

Preferably the metal member has two flanges extending longitudinally substantially parallel to one another and connected to a web to define a longitudinal channel section, and the elongate cover member constructed from a plastics material has two longitudinal flanges lying at right angles to and attached to a longitudinal web, to define a generally elongate channel which fits over the metal member and being so arranged that the side flanges and the web define sharp external right-angled corners. In a preferred embodiment, the edges of the flanges remote from the web are so shaped as to define a clip portion which engages the free edges of the flanges of the metal member to retain the cover in position.

The present invention will now be described further, by way of example only, with reference to the accompanying drawings, in which Figure 1 is a perspective view of a road form according to the invention, Figure 2 is a cross-sectional view of the road form according to the invention, and: Figure 3 is a cross-sectional view of another embodiment of a cover for a road form.

The road form shown in Fig. 1 comprises an elongate channel section 1, having two longitudinal flanges 2, 3 which are substantially parallel to one another and which are connected to a web 4. Conveniently, this channel section is bent to shape from one piece of metal. A connecting member 5 and a corresponding recess member 6 are provided at opposite ends of the channel section. Metal hoops are attached to the channel section and are provided with rectangular cut outs 8 into which fit wedges 9. Conveniently round steel stakes 10 are provided which fit through the hoops and are driven into the ground to locate the channel section. The channel section is free to move axially on the stakes until the wedges are driven into position, so determining the correct level for the channel.

Referring to Fig. 2, the channel section is again shown, but the enlarged view shows how a cover member 11 is provided which fits over the channel section 1. The cover member comprises a pair of longitudinal flanges 12, 1 3 lying at right angles to and attached to a longitudinal web 1 4 to define a further longitudinal channel section. Conveniently the cover member is moulded from a plastics material in one piece. The cover member is so arranged that the flanges and web intersect to define sharp external right-angled corners 1 5. As shown, the edges of the flanges 12, 1 3 are so shaped as to define a U-shaped clip portion 16, which engages the ends 1 7 of the flanges of the channel section 1 to retain the cover member 11 in position.

Referring now to Fig. 3 there is shown a preferred embodiment of a cover member 41 for the road form 1 of Figs. 1 and 2. The cover member 41, is substantially the same as the cover member 11 illustrated in Fig. 2. The cover member 41 has a pair of longitudinal flanges 42, 43 lying at right angles to and attached to a longitudinal web 44, so as to define a longitudinal channel section which fits onto the metal channel section 1. The internal corners 48 and the external corners 45 are formed as substantially sharp right angles. This contrasts with the cover member 11 of Fig. 2 which has radiused internal corners.

As illustrated, the longitudinal flange 42 has a U-shaped clip portion defining a first groove 50 at the edge of, the flange 42 remote from the longitudinal web 44. The groove 50 has a base 46 lying parallel to the web 44 and a side 47 lying parallel to the flange 42. The flange 42 of the metal channel section fits into the groove 50. The construction is similar to the flange 1 2 of Fig. 2.

The longitudinal flange 43 has, at its end remote from the longitudinal web 44, a clip portion 52 which defines a second groove 54.

The groove 54 is defined by a base 46 lying parallel to the web 44 and a side part 20 having a face 22 lying parallel to the longitudinal flange 43 and defining a side of the groove 54. The side part 20 has a further face 24 which is inclined with respect to the face 22 and, as illustrated, intersect the face 22 at 30. An end 35 of the face 24 remote from the flange 43 is located further from the web 44 than the intersection point 36. The depth of the face 22 in the direction towards the web 44 is preferably less than the depth of the side 47 in the same direction.

The provision of right-angled internal corners 48, and a side part 20 having an inclined face 24 and a side face 22 of reduced depth compared with the first embodiment enables the cover 41 to be fitted more easily onto the road form 1.

The preferred embodiment has been described as having only one flange 43 provided with the modified clip portion. As an alternative to the above described embodiment, both flanges 42, 43 may have the modified clip portion.

The cover member 41 is conveniently formed as a one piece moulding or extruded section.

In an alternative embodiment, the attaching means for securing the cover member to the metal member comprises at least one bracket extending substantially perpendicularly from one of the surfaces of the cover member. The bracket has a hole formed in it, and is arranged to project through a hole formed in a corresponding surface of the metal member. A tapered peg is inserted into the hole in the bracket when the cover member is in the metal member to retain it in position.

Advantageously, the cover member can be disposable because of its cheap construction.

The provision of the cover member also removes the necessity for frequent shot-blasting of the road forms.

It will be appreciated that other shapes of channel section and cover member may be utilised to provide the necessary sharp corner, other than the right-angled version described.

Claims (9)

1. A road form comprising an elongate metal member and a cover member of a plastics material adapted to fit onto at least part of the metal member, the cover member having at least two surfaces lying in different planes which intersect to form a sharp external corner.

2. A road form as claimed in claim 1 in which the cover member has two surfaces which intersect a third surface to form two sharp external corners.

3. A road form as claimed in claim 1 or 2, in which the surfaces of the cover member intersect to form a sharp right-angled corner.

4. A road form as claimed in any preceding claim, in which at least one of the surfaces of the cover member has attaching means for securing the cover member to the metal member.

5. A road form as claimed in claim 4, in which the cover member comprises two longitudinal flanges lying at right angles to and attached to a longitudinal web and the attaching means is a clip portion formed at an end of at least one longitudinal flange.

6. A road form as claimed in claim 4 or 5 in which the attaching means has a base and a side part which define in part a groove whose walls are parallel to the flange and web respectively, which groove receives an edge of a flange of the metal member.

7. A road form as claimed in claim 6 in which side part has an inclined face directed away from the mouth of the groove which enables the cover to be easily attached to the metal member.

8. A road form as claimed in any preceding claim in which the cover member is a onepiece moulding or extruded section.

9. A road form substantially as hereinbefore described with reference to and as illustrated in the accompanying drawings.